Does regional tissue oxygenation vary in infants transported by road and air. A prospective observational within-subject analysis of regional oxygenation measured by near infrared spectroscopy in infants transported in Western Australia.

ObjectiveInfants in Western Australia who are unwell frequently require air retrieval for tertiary care. Travelling at altitude may worsen hypoxia. Design, Setting and PatientsWe examined tissue oxygenation using near infrared spectroscopy (NIRS) during retrieval by road and air. Study design was prospective and observational comparing cerebral/mesenteric oxygenation (crS02 and mS02) and fractional tissue extraction (cFTOE and mFTOE) in newborns transported by fixed-wing aircraft and road ambulance. Transport by fixed-wing aircraft was a combination of by road and by air. Transport by ambulance was by road only. Primary outcome measure was a within-subjects comparison of oxygenation and tissue oxygen extraction (flight vs. road transit). Measurements in those transported by road were made as control (first and third quarter of road transit). ResultsThere were 24 infants transported by air and 31 by road. The median (interquartile range) gestations and weights were similar [39+1(31 - 41+3) vs. 40+1(35+3 - 43) wk; 3.3 (1.8 - 4.95) vs. 3.2 (2.2 - 4.2) Kg]. Most were treated for respiratory disease. There was no difference in SpO2, respiratory support or haemoglobin between groups. During transport by fixed-wing aircraft, infants had lower crS02 (75.3 (6.2) vs 77.9 (6.2); p=<0.0001) and mS02 (69.3 (16.6) vs. 74.2 (11.6); p=<0.01) and increased cFTOE (0.18 (0.07) vs. 0.21 (0.07), p<0.001) and mFTOE (0.22 (0.12) vs. 0.28 (0.17); P=0.006) than when travelling by road. There was no difference in the control group. ConclusionNewborn infants who travelled by air had lower cerebral saturations and greater oxygen tissue extraction when travelling by air. The pathogenesis and impact of these findings need further exploration. O_LIWhat is already known on this topic - Neonatal transport is not without risk and travelling at altitude may worsen cerebral hypoxia. C_LIO_LIWhat this study adds - NIRS monitoring during neonatal transport is feasible and air travel demonstrated lower regional saturation and increased oxygen extraction C_LIO_LIHow this study might affect research, practice or policy -NIRS monitoring as an adjunctive tool may contribute to safer neonatal transfers C_LI